Syringe structure



United States Patent l 3,344,786 SYRINGE STRUCTURE Robert H. Berg, 196Clinton Ave., Elmhurst, II]. 60126,

Carl Arthur Youngdahl, Elmhurst, and Lynn E. Ellison,

Crystal Lake, 111., said Youngdahl and said Ellison assignors to saidBerg Filed May 2, 1963, Ser. No. 277,656 1 Claim. (CI. 128-215) Thisapplication is a continuation-in-part of our pending application Ser.No. 170,749, filed Feb. 2, 1962.

The present invention relates to improvements in syringe structures andmore particularly concerns novel means for closing the discharge end ofa syringe barrel.

In conventional syringe structures, there is a substantial length ofdischarge passage or canal duct through the discharge nipple projectionon the barrel and the needle receiving fitting on the nipple. Withinthis discharge passage stagnation of material is a problem, especiallywith syringes in which the contents must be thoroughly agitated,emulsified, and the like.

An important object of the present invention is to provide new andimproved syringe structure having novel discharge passage closure means.

Another object of the invention is to provide a novel plug or stopperstructure for medical and like syringe discharge passages.

A further object of the invention is to provide a novel plug structurefor syringe discharge passages constructed and arranged for eflicientwiping or squeegeeing of material from the passage into the syringechamber.

Still another object of the invention is to provide novel means forplugging the discharge passage of a syringe closely adjacent to thelead-in or entrance into the passage from the syringe barrel chamber.

Other objects, features and advantages of the present invention will bereadily apparent from the following detailed description of certainpreferred embodiments thereof taken in conjunction with the accompanyingdrawing, in which:

FIGURE 1 is an enlarged elevational, partially sectional view of asyringe nipple closure and plug assembly according to the invention;

FIGURE 2 is a longitudinal sectional detail view showing the closure andplug assembled with a syringe barrel;

FIGURE 3 is a longitudinal sectional view similar to FIGURE 2 butshowing a modification; and

FIGURE 4 is an enlarged fragmental assembly detail view of the structureof FIGURE 3.

In the exemplification of the invention depicted in FIG- URES l and 2, aclosure assembly 5 is provided including a generally cup-shaped closurecap 7 dimensioned to receive snugly a tapered nipple 8 of a fitting 9attached to a nipple projection 10 extending centrally from a base endclosure 11 of a syringe barrel 12. Threaded interengagement of theclosure cap 7 with threads in a larger diameter skirt 13 of the fitting9 is efifected by means of laterally projecting lugs 14 adjacent theopen end of the cap.

Centrally, the barrel nipple 10 has an exit or discharge duct or passage15, also sometimes referred to as a canal, having at its entry agenerally funnel-shaped lead-in 17 from the base wall 11. At itsdischarge end the passage communicates coaxially with a central slightlylarger diameter passage 18 through the fitting nipple 8. At its innerend, the passage 18 is defined by a grooved sealing flange 19 engagingthe tip of the nipple 10 and aflording a barrier within a sealing gasket2ll=between the fitting and the end of the syringe barrel nipple. At itsoutlet end, the passage 18 is defined by a smoothly flaring mouth 21.

In order to reduce chances of stagnation of material Patented Got. 3,1967 in the discharge passage 15 of the syringe barrel nipple, theclosure assembly 5 includes an elastic plug 22 mounted on one endportion of a straight, thin rod-like stem 23, of much smaller diameterthan the passage bores 15 and 18, having its opposite end portionconcentrically rigidly secured in a crimped or pinched-in attachmentboss projection 24 on the closed end of the cap 7. By having the stem 23of proper length, the optimum terminal position of the plug 22 with itscrown adjacent to the outer end of the flared lead-in 17 from the floorof the end wall 11 into the passage 15 is gauged when the cap 7 is infully assembled relation with the fitting 9.

Construction of the plug 22 is such that it affords a positive wipingaction of the walls defining the discharge passage 18 in the fitting 9and also the passage 15 in the nipple 10 as an incident to thrusting ofthe plug into its plugging or stopper position at the inner end of thenipple passage 15; To this end, the plug 22 has a head diameter which isonly slightly less than the cylindrical diameter of the passage 15, thefree tip of the head having a leadin projection nose 25 of suitablytapered shape. Integral and contiguous to the head 22 is an annularflange 27 of such thickness that when Wholly or partially bent down andlapped against a tubular stem-encasing and gripping sleeve extension 28of smaller outside diameter than the head of the plug 22, a largerdiameter is described about the outside face of the collapsed flange.Through this arrangement, as the plug 22 is run up through the passage18 of the fitting nipple 8 and the coaxial passage 15 of the syringebarrel nipple 10, it acts as a squeegee by virtue of a thorough wipingaction to move adhering liquid on the passage walls ahead of the plugtoward the syringe chamber to the limit of movement of the plug in thesyringe passage 15.

As the plug 22 is maneuvered into position, utilizing the cap 7 as aconvenient handle, the flange 27 which is of substantially greaterdiameter than the bore of the passage 18 contacts the flaring entrymouth 21 on the tip of the nipple 8 and is uniformly contracted and bentrearwardly, on the order of an umbrella, and serves as a centeringmedium for the plug as the plug progresses up the bore of the passage13. By reason of its resilience and thus tendency to return towardnormal expanded position, the flange 27 wipingly thrusts against thebore 18 as indicated in dash outline in FIGURE 2, uniformly expands intothe groove of the sealing flange 19 and then as it follows the head ofthe plug 22 into the bore of the passage 15 is forced to contract andfold down onto the attachment sleeve 28 as shown in dot-dash outline. Inthis latter relationship a predetermined normal oversize diameter of theWiping surface of the wiping flange 27 backed up and cushioned againstthe sleeve 28 assures a firm, snug resiliently conformed wipingengagement against the wall defining the bore of the passage 15. Then,as the plug 22 advances into the flared lead-in 17, the flange 27 byvirtue of its resilience expands conformably to the progressivelyflaring diameter adjacent to the passage bore 15 whereby to maintain thesnug sealing engagement with the surrounding passage wall. The final orstopper terminal position of the plug 22 is predetermined through thelength of the stem 23 to be such, when the cap 7 has been fullytightened against the nipple 8, as to maintain the lip of the plugflange 27 in the area of reduced diameter of the leadin 17 which is atleast slightly less than the flange diameter.

In FIGURES 3 and 4, while details of the syringe itself are disclosed asidentical to FIGURE 2, a slightly modified closure assembly 30 isdepicted comprising a generally cup-shaped closure cap 31 of molded orcast structure of multi-sided, such as hex-headed, form, rather than thetubular essentially cylindrical and externally 3 knurled form of the cap7 of the closure assembly 5. A skirt 32 of the cap 31 has thread lugstructure 33 on its free end engageable with the threads within theskirt 13 'of the fitting 9 whereby to draw the skirt 32 firmly intoengagement with the nipple 8 of the fitting 9.

Firmly secured as by direct embedment in the center of the body of thecap 31 and projecting a predetermined distance from the attachmentsleeve 32 is a thin, rodlike straight stem 34 having mounted on its freeend portion an elastic squeegee-stopper plug 35. By having the stem 34of the proper length, the optimum position of the plug 35 with its crownat approximately the narrowest diameter of the flared lead-in 17 fromthe floor of the end wall 11 of the syringe barrel into the passage 15ispositively gauged when the cap member 31 is in its fully assembledrelation with the fitting 9, as shown in FIGURE 3.

Assurance of snug fit of the plug 35 within the passage bore is attainedby a sufiiciently oversizediameter I so as to compel its radialcompression by the cylindrical wall defining the passage 15. Forpositive wiping action as the plug is thrust toward its stopperposition, it is provided with-an annular radial rib flange 37 concentricwith the stem 34 and preferably of rounded cross-sectional externalshape, as shown. The over-all diameter of the rib flange 37 is at leastas great as the diameter within the groove in the sealing flange 19.Thus, as the plug 35 is driven up the passage 18 in the fitting 9, theflange 37 wipes the bore surface and drive any adhering liquid ahead ofthe plug. When the plug arrives within the sealing flange 19, the ribflange 37 expands into the groove thereof and wipes it cleans and forcesmaterial ahead of the plug into the passage 15 into which the roundedcrown of the plug head then leads. As the plug 35 is forced into thebore of the passage 15, the plug takes on a substantially cylindricalconforming shape under radial compression, as shown in dash outline inFIGURE 4 and in full outline in FIGURE 3, maintaining a thorough sealingengagement with the bore wall in the stopper position of the plug.

'The squeegee-stopper plugs 22 and 35 are made as by molding from anysuitable plastic or rubber material compatible with intended utilitye.g. in medical uses, buna-N or neoprene. Bonding of the plug in eachinstance onto the stem is improved by providing the plug-carrying endportion of the respective stem with a locking structure such as shallowgrooving or knurling 38 as shown in FIGURE 1 or shallow annular grooves39 as shown in FIGURE 4. A satisfactory durometer of about 40 to in thematerial of the plugs aflords sufficient elasticity to conform bycompression to the surfaces of the passages through which the plugs areprojected and then maintain an effective sealing engagement with thesyringe barrel exit passage in the terminal position of the plug byvirtue of the recovery factor or resilience or elasticity of thematerial.

Even though there is a shallow depression within the flaring lead-in 17over the crown of the fully assembled or terminal position of the plug,a shaking, stirring or emulsifying turbulence within the chamber of thebarrel 12 will sweep any material in the shallow depression so as toavoid any stagnation or undesirable accumulation or pocket of material.

When it is desired to apply a hypodermic needle to the fitting 9, theclosure fitting or assembly 5 or 30, as the case may be, is detached andthe stopper swab plug withdrawn from the discharge passage of thesyringe.

For illustrative purposes, the structures have been shown insubstantially enlarged form in the drawing and it will be appreciatedthat the dimensions in actual practice conform to standard or preferredpractice. For example, in one practical form, the diameter of the plugflange 27 and of the plug flange 37 is about of an inch, other diametersbeing substantially proportional, as

shown.

It will be understood that modifications and variations may be effectedwithout departing from the scope the novel concepts of the presentinvention.

We claim as our invention:

A syringe havong a barrel, a reduced end portion on said barrel having adischarge passage therethrough a fitting on said reduced end portionhaving apassage aligned with said discharge passage and forming with 7said reduced end portion a discharge nipple having a plurality ofdifferent internal diameters, said fitting having threads thereon, aclosure device having cooperative means removably engaged with saidthreads and comprising a closure cap engaged with said fitting; anelongated thin rod-like stem having one end portion firmly anchored tosaid cap and projecting substantially from said cap into the nipple, theopposite end portion of said stem carrying an elastomeric plug ofsubstantially larger diameter than said stem and having an annularflange dimensioned to act in wiping engagement with the multipleinternal diameters of said nipple and to provide a seala ing stopper atthe innermost portion of said multiple diameters by an umbrella-likefolding back of the wiping flange of said plug.

References Cited UNITED STATES PATENTS 2,583,162 l/1952 Verel 215472,843,508 7/ 1958 Sheft.

FOREIGN PATENTS 1,020,994 11/ 1952 France. 1,128,234 8/1956 France.

RICHARD A. GAUDET, Primary Examiner.

ROBERT E. MORGAN, Examiner.

